Preservation of wood with creosote fortified with copper compounds



ltl i li's iil SSIF (ILA

inn

Sl t

Unite;

PRESERVATION OF WOOD WITH CREOSOTE FORTH IED WITH COPPER COMPOUNDS Irving S. Goldstein, Pittsburgh, and William A. Dreher, Verona, Pa., assignors to Koppel-s Company, Inc., a

corporation of Delaware No Drawing. Ffled June 24, 1960, Ser. No. 38,443 2 Claims. (Cl. 106-15) The present invention relates to a composition for, a process for, and product of, the preservation of wood for marine installations from attack by marine organisms of both the sub-family Mollusca, such as the Teredo, Bankia, Martesia, Pholas, etc., and the sub-family Crustacea, such as the Limnoria, Chelura, and Sphaeroma. More particularly, the invention comprises a composition and process for, and product of, the pressure-impregnation of wood for such purpose with compounds resistant to said wood marine organisms of the sub-family Crustacea simultaneously with the impregnation by means of creosote as a liquid carrying medium for penetrating the wood with said compounds in impregnating the same.

An object of the invention of the preservation of marine wood as aforesaid in a simple, economical, and facile way, using a liquid preservative efiective for retarding attack by molluscan bores as the medium for impregnating the wood with additives found to be effective for retarding attackby the crustacean borers, as a result of the combined application of the carrier medium and the additive.

A,further object'of the invention is the provision of a composition method and product as aforesaid in which selected additives that are both effective for said retarding effects and can be carried by the creosote in amounts high enough to be effective for preserving the wood for long-life expectancy.

When untreated wood is placed in salt water, it may be quickly attacked by marine bores of either of theaforesaid sub-families. It has been a common practice to'protect wood by impregnating the wood with creosote, creosote being a distillate of coal tar that is produced by the high-temperature carbonization of coal. The creosote, as used for wood preservation, consists of liquid and solid aromatic hydrocarbons, contains variable quantities of tar acids and ta'r bases, is heavier than water, and has a continuous boiling range of at least 125 C. beginning at about 200 C. Sometimes, the creosote has mixed therein, as much as an equal part by weight of coal tar. The creosote or coal tar-creosote, when impregnated into the wood, is toxic to fungi and most organisms. Experience has shown that pressure-impregnation of wood with certain liquid compositions, such as a high residue creosote or a 70-30 blend of creosote and coal tar, gives a long-range protection to wood against attack by members of the molluscan family, but the wood may still be attacked by members of the crustacean family which has greater tolerance to creosote. Thus, while creosote is suitable for the purpose of preventing the attack of wood by, for instance Teredo, other marine organism, such as Limnoria, may still attack creosoted piles.

It has now been found that organic-copper compounds can be dissolved in creosote and the solution used to penetrate wood to protect the wood against both molluscan and crustacean organisms.

More specifically, it has been found that the oil- Patented Nov. 20, 1962 soluble organo-copper compounds of the group efiective to prevent attack of wood by marine organisms, each as Limnoria, and that are also soluble in creosote to provide up to one percent by weight of copper in solution as as to provide at least one-half percent of copper, are effective in protecting the wood for varying degees of time in marine use of the wood while the creosote is still protecting the wood in such marine use from attack by marine organisms, such as Teredo.

The organo-copper compounds of this group, which consists of those listed in the first two columns of Table IV hereinafter noted, have been found to be superior for the purpose over others of this group in providing a longer time range of protections.

The compounds of the group consisting of copper ethyl acetoacetate, copper o-benzoylbenzoate, copper 2,4-dinitrophenolate, copper pentachlorophenoxyacetate, copper 4,6,dinitro-o-cresolate, and copper phenoxyacetate, are

much superior for the purpose than the other compounds of the group listed in the first two columns of Table IV.

The nitrated and chlorinated aromatic copper compounds were more effective than the aliphatic compounds, especially those of the group consisting of copper 2,4- dinitrophenolate, copper pentachlorophenoxyacetatc, and copper 4,6-dinitro'o-cresolate, and they have been found to be of greater solubility in the creosote impregnated in the marine-use wood.

According to the invention therefore, there is provided a composition for use in the combined preservation of wood in marine use against attack from both molluscan and crustacean borers, comprising creosote fortified with at least one additive of the group of organo-metallic compounds that are effective to retard crustacean borers, and more particularly, compounds of the group which consist of those listed in the first two columns of the Table IV hereinafter noted, and preferably, those of the group consisting of copper ethyl acetoacetate, copper o-benzoylbenzoate, copper 2,4-dinitrophenolate, copper pentachlorophenoxyacetate, copper 4,6-dinitro-o-cresolate, and copper phenoxyacetate, and especial-compounds, particularly the group consisting of copper 2,4-dinitrophenolate, copper pentachlorophenoxyacetate, and copper 4,6-dinitro-ocresolate.

The composition according accordingto the invention comprises the crustacean retarder additives in the proportion provide at least one-half to one percent copper in solution by weight of the solution, and preferably, one percent by weight of copper provided by crustacean retarder additive, since this amount is required in the wood for marine use in order to protect it for longer periods of time. Larger percentages up to the limit of solubility of the compound in creosote may be used, if desired. The upper limit is generally an economic consideration as the copper compound is usually more expensive than the creosote.

The new compositions may be used in the preservation of timber, piles, and other wood products, for marine use by conventional empty and full cell methods of impregnation. For example, to provide for a full cell treatment, the wood is placed in a standard treating cylinder and a vacuum pulled until a manometer shows at least 22", for about one-half hour. This is then followed by submerging the wood with the solution under pressure for several hours at up to 290 p.s.i.g. at about 3 200 F., to penetrate the wood with the solution until the wood becomes impregnated by a solution of creosote fortified with an additive comprising crustacean retardants aforesaid. At the conclusion of the process, the cylinder and wood may be subjected to a vacuum to remove excess impregnant material from the wood.

The invention also comprises, the product of the process, that is, a product for marine use, comprising wood having an impregnant therein consisting of creosote fortified with an additive of crustacean retardants aforesaid.

Tests to determine the compounds which resist the destructive action of marine organisms on structures submerged in sea water are difiicult because the treated wood must be exposed for an extended period to marine organisms of great activity. It is well known, for example, that the marine organisms of those geographical regions having a temperate or arctic climate are not as destructive to wood as are the marine organisms in regions having more tropic climate Further, the region in which the exposure is made, must be a region abounding with the marine organisms. Also, the test piece must be open to atack for a period of time, extended for a number of years. To demonstrate this, inventors panels were treated and then exposed to the sea in a region abounding in marine life. Since such panels have a high surface to volurne ratio as compared to piling or post, and so, were exposed to leaching at a greater rate, and so, provided a greater surface area for attack by the marine organisms, the results were accelerated. Even so, as indicated by the tables below, some materials which appearedto be satisfactory for a period of seven years, were found to have become unsatisfactory, when exposed for a period of eight years. To perform these tests, the exemplary compounds listed in Table I were selected, on the basis of creosote solubility and economic considerations, to fortify creosote, and were dissolved in the creosote to form solutions comprising approximately one percent by weight copper. Specimens of commercial 100% sap southern pine, which had been kiln dried immediately after sawing and at the time of cutting had an average moisture content of about seven percent were impregnated with these combinations in a treating cylinder using a treating cycle consisting of a vacuum pulled until the manometer showed 26" (usually five to ten minutes), followed by a two-hour pressure period at 150 p.s.i.g. and 150 F. The specimens were then tagged. The creosote used, showed on analysis, the following characteristics:

Two complete sets of these specimens were exposed in a salt water environment of known high marine biological activity at Aransas Pass, Texas.

After seven years exposure, one complete set of copper-fortified creosoted specimens was removed from test and examined. The examination was visual and a rating was made as to the extent of attack by Limnoria, i.e., no attack, slight attack, moderate attack, and heavy attack. The copper-fortified specimens showed relative freedom from attack, but while the addition of organo-copper compounds to creosote did improve its performance in marine waters, it was concluded that it was too early to select the outstanding compounds. After eight years of exposure, the other set of copper-fortified creosoted panels was removed. The condition of the panels is decribed in Table I.

' From these marine-exposure panels treated with copperfortified creosote, six compounds show superior performance in extending the life of creosoted wood against attack by Limnoria. The most efiective fortifying compounds are copper ethyl acetoacetate, copper o-benzoylbenzoate, copper 2,4-dinitrophenolate, copper pentachlorophenoxyacetate, copper 4,6-dinitro-o-cresolate, and copper phenoxyacetate.

TABLE I Condition of Pine Panels Treated With Creosote Fortified With Organo-Copper Derivatives After Eight Years Exposure to Marine Organisms Copper Fortitymg Agent In (Soln. Condition of Panel D cent) None 0. Heavy Limnoria attack. Copper o-chlorobenzoate.. 1. o. I Copper 2-chloro-5mitrobcnzoate- 0. Numerous Limnoria.

Copper ethyl aeetoaeetate 0. No attack. Copper 2,4-dichlorophenoxyaoetate.- 0. Few Limnoria. Copper 2,4-dichlorobenzaote 0. No attack. Copper phenoxyaeetate-. 0. Few Lirnnoria. Copper salicylate 0. N 0 attack. Copper o-benzoylbenzoate 0. Few Limnoria. Copper 2,4-dinitrophenola 1. No attack. Copper pentaclilorophenoxy 1. Do. Copper 2,4,S-trichlorophenoxyaeetate 0. Few abortive Limnoria. Copper 3-phenylsalicylate 1. Moderate Limnoria attack. Heavy Limnoria attack.

Copper S-quinolinolate Moderate Limnoria at- Copper nonylphenoxyacetate 0Q 00 wlaqom a tomorrow:- HOHIO tack. Copper phenylacetate Do. Copper octyl phthalate..-. No attack.

Few Limnoria.

Heavy Limnoria attack.

Moderate Limnoria attack.

N 0 attack.

Copper 4,6-dinitro-o-cresolate.

Copper oliaie Copper cyclohexyl 3 and 4-ch1orophthalate.

Ctlip per cyclohexyl tetrachlorophthaate.

As a result of the eight years exposure to a marine environment of high biological activity, it was possible to apply a comparative performance rating of superior, intermediate, and poor to the copper compounds. This rating is illustrated in Table 11.

TABLE 11 Perofrmance Rating of Fortifying Compounds After Eight Years Exposure Superior Intermediate Poor Copper ethyl aceto- Copper 2-chloro-& Untorttfied acetate. nitrobenzoat/e. Creosote. Ca iper 2,4-dichloro- Copper nonylphe- Copper o-chlorop epoxy-acetate. noxyaeetate. nzoate. Copper 2,4-d1chloro- Copper cyclohexyl Copper 3-phenylbenzoate. 3 and 4. salicylate. Copper phenoxyaeetate; chlorophthalate. Copper B-qulno- Copper salteylate. Copper phenyllmolate. Copper o benzoylacetate. Copper oleate.

bcnzoate. Copper 2,4 dinitrop enolato.

Copper pentaehlorophenoxy-acetate.

Copper 2,4,5-trichlorophenoxyacetate.

Copper octyl phthalate.

Copper 4,6-dinitro-ocresolate.

Copper cyclohexyl tetrachlorophthalate.

The following Table III, where the results of panels at the end of eight years are compared with the results at the end of seven years, illustrates the difficulty in ascertaining a biological action. The performance of some materials did not change, where as the performance of other materials changed. The materials in the panels of Group A, which were superior at the end of the seven year period, were also superior at the end of the eight year period, and the materials in the panel of Group B, which were intermediate at the end of the seven year period, were also intermediate at the end of the eight year period. The materials in the panels of Groups C," D, and E showed better results at the end of the eight year period than at the end of the seven year period. The materials in the panels of the Group F, G, and H, however, showed a worse performance at the end of the eight year period than at the end of the seven year period.

TABLE III Relative Performance 0 Fortib'z'ng Compounds After Eight and Seven Years Exposure Improved Performance Diminished Perform- Same Performance In Eight Year ance In Eight Year Inspection Inspection Superior (A) Intermediate to Superior to Superior (C) Intermediate (F) Copper ethyl aceto- Co per 2,4-dich1oro- Copper 2-chloro-5- acetate, p enowacetate. nitro-benzoate. Copper o-benzoyl- Copper 2,4-diehloro- Copper phenylaeebenzoate. benzoate tat-e. CopJper 2,4-dinitro- Copper salicylate. p enolate. Superior to Poor Copper tgDDGIIOXY- Poor to Superior (D) (G) aoeta Copper pentachloro- Copper 2,4,5-trlchloro- Copper o chlorop enoxyacetate. phenoxyaeetate. nzoa Copper 4,6-dinitro-o- Copper octyl phthal- Cgpger 3-phenylcresolate. ate. cylate.

. Copper cyclohexyl Intermediate (B) tetrachlorophthal- Intermediate to ate. Poor (H) Copper eyolohexyl 3 and 4-ehloro- Poor to Intermediate Copper S-qumophthalate. (E) linoiate.

Copper oleate. Copper nonylphenoxyecetate.

A comparison of the effectiveness of the addition in retarding attack by crustacean organisms, is shown in Table IV, below:

TABLE IV Performance of Fortifying Compounds in Eight and Seven Year Exposures to Marine Organisms 1. A composition for the protection of wood from attack by molluscous and crustaceous marine organisms which consists essentially of creosote fortified by dissolving therein at least 1% 'by weight of an oil-soluble organocopper-compound selected from the group consisting of:

Copper ethyl acetoacetate Copper 2,4-diehlorophenoxyacetate Copper 2,4-dichlorobenzoate Copper phenoxyacetate Copper salicylate Copper o-benzoylbenzoate Copper 2,4-dinitrophenolate J Copper pentachlorophenoxyacetate Copper 2,4,5-trichlorophenoiryacetate Copper octyl phthalate Copper 4,6-dinitro-o-eresolate Copper cyclohexyl tetrachlorophthalate Copper 2-chloro-5-nitrobenzoate Copper nonylphenoxyacetate Copper cyclohexy 3 and 4 chlorophthalate Copper phenylaeetate 2. A wood adapted for marine use and resistant to attacks by both molluscous and crustaceous organisms which is comprised of wood impregnated with the composition of claim 1.

Perkins Sept. 2-2, 1942 Magner Aug. 25, 1959 

1. A COMPOSITION FOR THE PROTECTION OF WOOD FROM ATTACK BY MOLLUSCOUS AND CRUSTACEOUS MARINE ORGANISMS WHICH CONSISTS ESSENTIALLY OF CREOSOTE FORTIFIED BY DISSOLVING THEREIN AT LEAST 1% BY WEIGHT OF AN OIL-SOLUBLE ORGANOCOPPER COMPOUND SELECTED FROM THE GROUP CONSISSTING OF: 